Abbott Laboratories on Wednesday laid off 550 workers across several of its business units and said it plans to cut "several hundred" additional workers in 2013. The North Chicago-based company said the job cuts, 100 of which were in Chicagoland, affect workers in its nutrition, medical devices, established pharmaceuticals and diagnostics units. None were in the company's proprietary pharmaceutical division, which will be spun off Jan. 1 as an independent company called AbbVie, a spokesman said. Abbott revealed the cuts in its third-quarter earnings release. The company took a $478 million pre-tax charge in the quarter to pay for the restructuring. That amount includes costs related to earlier job cuts and those expected in 2013. "The businesses independently assessed the environment and competitive landscape," said Scott Stoffel, an Abbott spokesman. "Today's changes will enable our businesses to align their resources to better meet evolving business needs." The cuts were announced to workers Wednesday morning, just after the company said its third-quarter income beat Wall Street expectations by 2 cents despite a drop in revenue, as the company drastically cut expenses ahead of its planned split.